Sex differences in assessment of obesity in rheumatoid arthritis

Abstract

Objective Determine prevalence of obesity and how accurately standard anthropometric measures identify obesity among men and women with RA. Methods Dual-energy x-ray absorptiometry (DXA) was performed for 141 persons with RA (56 men, 85 women). Two anthropometric proxies of obesity (body mass index [BMI], waist circumference [WC]) were compared to a DXA-based obesity criterion. Receiver operating characteristic (ROC) curves determined optimal cut-points for each anthropometric measure, relative to DXA. Association of body fat and anthropometric obesity measures with disease status and cardiovascular risk was assessed in multiple regression analyses, controlling for age and glucocorticoid use. All analyses were performed separately for men and women. Results 20%, 32%, and 44% of women, and 41%, 36%, and 80% of men were classified as obese by BMI, WC, and DXA, respectively. Cut-points were identified for anthropometric measures to better approximate DXA estimates of percent body fat (BMI: women, ≥26.1 kg/m2; men ≥24.7 kg/m2. WC: women, ≥83 cm; men, ≥96 cm). For women and men, higher % fat was associated with poorer RA status. Anthropometric measures were more closely linked to RA status for women, but identified cardiovascular risk for both women and men. Conclusions A large percentage of this RA sample was overfat; DXA-defined obesity was twice as common in men than in women. Utility of revised BMI and WC cut-points compared to traditional cut-points remains to be examined in prospective studies, but results suggest that lower, sex-specific cut-points may be warrented to better identify individuals at risk for poor RA and/or cardiovascular outcomes.

Are Men at Greater Risk of Lean Mass Deficits in Rheumatoid Arthritis?

“…(14-16) For example, we previously reported that men with RA were at greater risk of obesity, compared with women. (12) Similarly, two previous studies demonstrated significantly lower estimates of lean body mass in men with RA compared to matched controls, but this association was absent in women. (10, 17) Despite these observations, assessment of sex differences in the extent of lean mass deficits among men and women has been limited by the lack of robust sex-specific reference ranges and consideration of sex differences in risk factors for abnormal body composition.…”

“…Details of the cohort have previously been published. (12) Briefly, the majority of the research participants in this dataset were drawn from the University of California, San Francisco (UCSF) RA Panel Study. After telephone interviews in the study years 2007–2009, RA Panel participants who lived in the greater San Francisco area were recruited for in-person assessments, including measurement of body composition.…”

Making the invisible visible: bioelectrical impedance analysis demonstrates unfavourable body composition in rheumatoid arthritis patients in clinical practice

“…Stavropoulos-Kalinoglou et al (21) and Katz et al (22) suggested new RA-specific BMI cut-off points that are lower than the current WHO cut-off values, therefore classifying an even larger proportion of RA patients as overweight and obese. However, standard anthropometric measurements, including body weight and BMI, are insensitive to demonstrating the changes in body composition that often occur in (weight-stable) RA patients (23).…”

Frailty and reduced physical function go hand in hand in adults with rheumatoid arthritis: a US observational cohort study

“…Details of this cohort are reported by Katz et al [12]. Briefly, participants for this cohort were drawn primarily from the UCSF RA Panel study.…”